Dental appliance with simulated teeth and method for making

ABSTRACT

The present invention relates to orthodontic positioning appliances that represent teeth in desired positions and related systems and methods. An appliance can include teeth receiving cavities shaped to receive and apply a resilient positioning force to a patient&#39;s teeth. An appliance can include an outer component having a surface representing teeth in desired positions. An outer component can be integral with an appliance. An outer component can be separate and configured to couple with an appliance main body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/277,153, filed Nov. 24, 2008, the full disclosure of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of orthodontics,and more particularly removable tooth positioning appliances with theappearance of a desired tooth arrangement as well as related methods,including methods of use and fabrication.

An objective of orthodontics is to move a patient's teeth to positionswhere function and/or aesthetics are improved. Traditionally,orthodontists applied metal brackets to the patient's teeth, and coupledthem by a wire and elastics to exert diminishing force on the teeth in ageneral direction. This force gradually urges the teeth toward a desiredstage of treatment. With a series of clinical visits and reactiveadjustments to the wire and elastics, the orthodontist can move theteeth through various treatment stages until a final functional anddesirable tooth arrangement is obtained.

More recently, alternatives to conventional orthodontic treatment withtraditional affixed appliances (e.g., braces) have become available. Forexample, systems including a series of preformed appliances/alignershave become commercially available from Align Technology, Inc., SantaClara, Calif., under the trade name Invisalign® System. The Invisalign®System is described in numerous patents and patent applications assignedto Align Technology, Inc. including, for example in U.S. Pat. Nos.6,450,807, and 5,975,893, as well as on the company's website, which isaccessible on the World Wide Web (see, e.g., the url“www.invisalign.com”). The Invisalign® System includes designing and/orfabricating multiple, and sometimes all, of the aligners to be worn bythe patient before the aligners are administered to the patient and usedto reposition the teeth (e.g., at the outset of treatment). Often,designing and planning a customized treatment for a patient makes use ofcomputer-based 3-dimensional planning/design tools, such as Treat™ fromAlign Technology, Inc. The design of the aligners can rely on computermodeling of a series of planned successive tooth arrangements, and theindividual aligners are designed to be worn over the teeth andelastically reposition the teeth to each of the planned tootharrangements.

Both traditional and recently developed alternative methods oforthodontic treatment require an amount of time, sometimes up to two tothree years or more, to accomplish repositioning of a patient's teeth,during which the patient must continue to tolerate the existingappearance of their teeth. With traditional orthodontics, the patient'sappearance includes the patient's teeth in unfinished positions, whichmay include extruded or extracted teeth or interproximal spaces andvisible braces. Even when braces are avoided by using alternativetreatment methods, the patient's teeth are visible in their naturalcolor and unfinished positions until treatment has progressed orfinished.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a removable orthodontic tooth positioningappliance with improved or selected appearance and related methods andsystems. In contrast to an appliance where a patient's teeth are visiblein their unfinished positions, a positioning appliance in accordancewith the present invention can include a depiction of a set of teeth(e.g., the patient's teeth) having a desired appearance and/or in aselected arrangement, such as their finished or desired positions. Thus,in one embodiment, the present invention presents a treatment optionwith improved appearance during orthodontic treatment, eliminating thewait during which the patient's teeth are being repositioned towardtheir planned positions before an improved appearance is presented.

Thus, in one aspect, the present invention includes a removableorthodontic tooth positioning appliance, and related systems andmethods, with an improved or selected outer appearance to representteeth in a desired arrangement.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be made to the ensuing detailed descriptionand accompanying drawings. Other aspects, objects and advantages of theinvention will be apparent from the drawings and detailed descriptionthat follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an diagram showing the anatomical relationship of the jaws ofa patient.

FIG. 2A illustrates in more detail the patient's lower jaw and providesa general indication of how teeth may be moved by the methods andapparatus of the present invention.

FIG. 2B illustrates a single tooth from FIG. 2A and defines how toothmovement distances are determined.

FIG. 2C illustrates the jaw of FIG. 2A together with an incrementalposition adjustment appliance without improved appearance.

FIGS. 3A-3C illustrate the installation of an incremental positionadjustment device with improved appearance in accordance with thepresent invention on a patient's upper teeth.

FIG. 4A illustrates a top down view of a person's lower teeth in anexemplary malocclusion while wearing an appliance in accordance with thepresent invention.

FIG. 4B illustrates a top down view of an inventive appliance being wornover the person's lower teeth after being moved by the appliance of FIG.4A and shows how appliance thicknesses can be increased to maintain adesired outer surface appearance in accordance with one embodiment ofthe present invention.

FIG. 4C illustrates a top down view of an inventive appliance being wornover the person's lower teeth after being moved by the appliance of FIG.4B and shows how appliance thicknesses can be decreased to maintain adesired outer surface appearance in accordance with another embodimentof the present invention.

FIG. 5A illustrates separate components of one embodiment of the presentinvention, where the outer component is a veneer configured to beattached to the main body of the incremental position adjustment device.

FIG. 5B illustrates the embodiment of FIG. 5A, where the outer componenthas been attached to the main body.

FIG. 6 is a block diagram illustrating steps for configuring andfabricating an incremental position adjustment device with improvedappearance in accordance with an embodiment of the present invention.

FIG. 7 is a block diagram illustrating steps for determining desiredappearance in accordance with an embodiment of the present invention.

FIG. 8 is a block diagram illustrating steps for integrating desiredappearance with an appliance in accordance with an embodiment of thepresent invention.

FIG. 9 illustrates alternative processes for producing an applianceand/or outer component with the appearance of a desired tootharrangement according to methods of the present invention utilizingdigital data sets representing the appliance and/or outer component.

FIG. 10 is a simplified block diagram of a data processing systemincorporating an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention described herein provides a device, system, method and kitfor a dental appliance with an outward appearance of a desired tootharrangement that is different from the current teeth arrangement. Asdescribed in more detail below, the present invention can uponapplication instantly change or improve the appearance of a patientduring orthodontic treatment through the use of a representation ofteeth in a desired arrangement.

Functional Appliance without Improved Appearance Component

FIG. 1 provides an appropriate starting point in a discussion of thepresent invention with respect to appliances designed to applypositioning forces, or repositioning forces, to teeth. FIG. 1 depicts askull 10 with an upper-jaw bone 22 and a lower-jaw bone 20. Thelower-jaw bone 20 hinges relative to skull 10 at joint 30. Lower jawbone 20 and upper jaw bone 22 further support lower jaw 100 and upperjaw 101 respectively.

Referring now to FIG. 2A, lower-jaw bone 100 includes a plurality ofteeth 102, as is the case with most people. However, in many people, thearrangement of teeth 102 may include one or more teeth having positionsand orientations that deviate from their optimum positions, therebypossibly forming an improper occlusion (malocclusion). Where significantdeviations from optimal positions exist for one or more teeth 102,orthodontics treatment is often employed to move teeth towards theiroptimal positions. As a frame of reference describing how a tooth may bemoved, an arbitrary centerline (CL) may be drawn through the tooth 102.With reference to this centerline (CL), each tooth may be moved inorthogonal directions represented by axes 104, 106, and 108 (where 104is the centerline). The centerline of the tooth may be rotated about theaxis 108 (angulation), axis 106 (inclination), and the axis 104(rotation). Thus, all possible free-form motions of the tooth can beperformed.

FIG. 2B shows how the magnitude of any tooth movement may be defined interms of a maximum linear translation of any point P on a tooth 102.Each point P1 will undergo a cumulative translation as that tooth ismoved in any of the orthogonal or rotational directions defined in FIG.2A. That is, while the point will usually follow a nonlinear path, thereis a linear distance between any point in the tooth when determined atany two times during the treatment. Thus, an arbitrary point P1 may infact undergo a true side-to-side translation as indicated by arrow d1,while a second arbitration point P2 may travel along a curved path,resulting in a final translation d2. Many aspects of the presentinvention are defined in terms of the maximum permissible movement of apoint P1 induced on any particular tooth. Such maximum tooth movement,in turn, is defined as the maximum linear translation of that point P1on the tooth that undergoes the maximum movement for that tooth in anytreatment step.

FIG. 2C shows one adjustment appliance 111 which is worn by the patientin order to achieve an incremental repositioning of individual teeth inthe jaw 100. The appliance can include a shell (e.g., polymeric shell)having teeth-receiving cavities that receive and resiliently repositionthe teeth. In one embodiment, a polymeric appliance can be formed from aknown thin sheet of suitable elastomeric polymeric material, such a 0.03inch thermal forming dental material by Tru-Tain Plastics, Rochester,Minn. An appliance can fit over all teeth present in an upper or lowerjaw, or less than all of the teeth. In some cases, only certain teethreceived by an appliance will be repositioned by the appliance whileother teeth can provide a base or anchor region for holding theappliance in place as it applies force against the tooth or teethtargeted for repositioning. In some cases, many, most, or even all ofthe teeth will be repositioned at some point during treatment. Teethwhich are moved can also serve as a base or anchor for holding theappliance as it is worn by the patient. Typically, no wires or othermeans are provided for holding an appliance in place over the teeth. Insome cases, however, it may be desirable or necessary to provideindividual anchors on teeth with corresponding receptacles or aperturesin the appliance so that the appliance can apply a selected force on thetooth. Exemplary appliances, including those utilized in the Invisalign®System, are described in numerous patents and patent applicationsassigned to Align Technology, Inc. including, for example in U.S. Pat.Nos. 6,450,807, and 5,975,893, as well as on the company's website,which is accessible on the World Wide Web (see, e.g., the url“www.invisalign.com”). Appliances according to the present invention arefurther designed to include aspects such that the appliance isconfigured to operate in conjunction with one or more tooth movementdevices disposed in the appliance itself and/or in an attachment mountedto a surface of a patient's tooth, as described herein.

An appliance can be designed and/or provided as part of a set orplurality of appliances. In such an embodiment, each appliance may beconfigured so a tooth-receiving cavity has a geometry corresponding toan intermediate or final tooth arrangement intended for the appliance.The patient's teeth can be progressively repositioned from an initialtooth arrangement to a target tooth arrangement by placing a series ofincremental position adjustment appliances over the patient's teeth. Atarget tooth arrangement can be a planned final tooth arrangementselected for the patient's teeth at the end of all planned orthodontictreatment. Alternatively, a target arrangement can be one of manyintermediate arrangements for the patient's teeth during the course oforthodontic treatment, which may include where surgery is recommended,where inter-proximal reduction (IPR) is appropriate, where a progresscheck is scheduled, where anchor placement is best, where palatalexpansion is desirable, etc. As such, it is understood that a targettooth arrangement can be any planned resulting arrangement for thepatient's teeth that follows one or more incremental repositioningstages. Likewise, an initial tooth arrangement can be any initialarrangement for the patient's teeth that is followed by one or moreincremental repositioning stages. The adjustment appliances can begenerated all at the same stage or in sets or batches (e.g., at thebeginning of a stage of the treatment) and the patient wears eachappliance until the pressure of each appliance on the teeth has fullybeen expressed or has resulted in the maximum allowable tooth movementfor that given stage. A plurality of different appliances (e.g., set)can be designed and even fabricated prior to the patient wearing anyappliance of the plurality. After wearing an appliance for anappropriate period of time, the patient replaces the current appliancewith the next appliance in the series until no more appliances remain.The appliances are generally not affixed to the teeth and the patientmay place and replace the appliances at any time during the procedure(e.g., patient-removable appliances).

Selected/Improved Appearances for the Functional Appliance

Referring now to FIG. 3A, a simplified illustration depicting a typicalmalocclusion 122 and the installation of a removable orthodonticpositioning appliance 124 for the upper teeth 120 in conformance withthe present invention is provided. A person of ordinary skill in the artwould appreciate that although this figure only depicts a set of upperteeth, the invention would equally apply to a set of corresponding lowerteeth as well. As discussed above, a patient will install/wear anyparticular appliance for a period of time during which the applianceapplies forces to the patient's teeth urging them along their pathstoward their planned final positions by some incremental amount. Thepresent invention provides a means by which to mask the actual existingappearance of the patient's teeth in their present positions byincorporating into the appliance a representation of teeth in desiredlocations on visible portions of the shell appliance. During use, thepatient places the appliance with its associated representation of teethover their teeth, thereby covering the patient's currently misplacedteeth with an appliance that depicts teeth in a desired arrangementwhile simultaneously functioning to reposition the patient's teethtoward their own desired locations.

FIG. 3B, and FIG. 3C provide further illustration of the appearanceenhancing qualities of the present invention. More specifically, FIG. 3Bdepicts the same individual from FIG. 3A, but is shown wearing theremovable orthodontic positioning appliance 124 in conformance with thepresent invention. By comparing the appearance presented in FIG. 3B withthe appearance presented in FIG. 3A, one can recognize that the teeth ofFIG. 3B provide the appearance that the teeth are visually differentfrom the actual arrangement of the patient's teeth at the given stage oftreatment (e.g., desired orthodontic arrangement).

FIG. 3C further depicts how the appearance of the person of FIG. 3A canbe altered by wearing a positioning appliance with a selected orimproved appearance 130 in conformance with the present invention. Thealternate embodiment shown incorporates a novelty arrangement in theform of a simulated gold tooth 132 and two fangs 134. Similar variationsin appearance to that shown in FIG. 3C are possible, such as theincorporation of other novelty arrangements such as those selected forspecial occasions (e.g., exaggerated features like fangs, buck teeth,missing teeth, gapped teeth, crooked teeth, non-human teeth, gold orjeweled teeth, or chipped teeth). Another possible variation involvesthe use of red, white, and blue teeth segments, which might be used atleast during the Fourth of July holiday or during other patrioticcelebrations. Still another novelty arrangement would be to capture theappearance of an aesthetically desired arrangement, such as a model orcelebrity tooth arrangement. With these examples, it should beappreciated that the concept of an improved or selected appearance canbe subject to the particular desires of the patient without altering thedesired orthodontic positioning and/or repositioning that the doctor maybe trying to accomplish while the patient wears the appliances. Thus,the patient may request that the e by not modifying the basic appliancein areas where appearance is less important. An important considerationin selecting the arch span for the desired appearance is whether therewill be a separate outer predetermined final tooth arrangement.

Integration of Functional Appliance with Selected/Improved AppearanceComponent

FIGS. 4A, 4B and 4C illustrate top down views of inventive appliances140, 150, 160 being worn over a patient's teeth. FIG. 4A depictsappliance 140 being worn over the patient's teeth that have an exemplaryinitial malocclusion. Appliance 140 includes an outer surface 142 havinga desired appearance. Outer surface 142 can be selected so as toenvelope the patient's teeth. The outer surface selection can be made soas to result in a desired minimum thickness 144 and to minimize maximumthickness 146 to the extent possible given the malocclusion.

Depending on the malocclusion, the teeth may be tilted in to the mouthand rotated so that the desired final arch that is used to calculate thedesired outer surface appearance at the prescribed teeth arrangementwould never change, and thus the outer most position of the desiredouter surface may not move outward during treatment. However, it is morelikely that the outer surface of the appliance will extend furtheroutward than the teeth will at any stage of treatment, wherein the outersurface of the appliance will only extend outward by the thickness ofthe material at the last stage.

FIG. 4B illustrates a top down view of the appliance 150 being worn overthe person's lower teeth after being moved by the appliance 140 of FIG.4A. FIG. 4B illustrates how appliance thicknesses (e.g., thickness 154)can be increased to maintain a desired outer surface appearance, such aswhen outer surface 152 is selected to be the same as outer surface 142used for appliance 140 and the patient's teeth have been moved inwards.

FIG. 4C illustrates a top down view of the appliance 160 being worn overthe person's lower teeth after being moved by the appliance 150 of FIG.4B. FIG. 4C illustrates how the thicknesses of an appliance (e.g.,thickness 164) can be decreased to maintain a desired outer surfaceappearance, such as when outer surface 162 is selected to be the same asouter surface 152 or 142 and the patient's teeth have been movedoutwards.

FIG. 5A and FIG. 5B illustrate one embodiment of a positioning appliance170 for the lower teeth with improved appearance, where the desiredappearance is provided by an attachable outer component 172. Theattachable outer component shown is a veneer-type component 172. As usedherein, a veneer-type component 172 (hereinafter “veneer”) refers to acomponent that incorporates a desired appearance and may includeattachment surfaces 174 that are substantially shaped to match matingexterior surfaces 176 of an appliance. The veneer shown incorporatesouter surfaces that represents a patient's own teeth in their plannedfinal arrangement. Alternatively, an outer component can be shaped torepresent an ideal or selected set of teeth as described elsewhereherein. In FIG. 5A, the veneer outer component 172 is shown offset fromthe main body of the positioning appliance 170 so as to illustrateexemplary shapes for both a veneer-type outer component 172 and a mainbody of an appliance 170. FIG. 5B illustrates the combination of theveneer-type outer component 172 and the main body of the appliance 170.

As can be seen in FIG. 4A through FIG. 5B, the outer component can beconfigured to cover just a portion of the lingual surface and theanterior portion of the patient's arch or the full arch. Partial archspan coverage may be preferred since the posterior portions of thepatient's arch are generally less visible, and such minimal coveragewould require less material and thus weigh less in the mouth. To furtherdecrease the amount of material used so as to decrease weight and/orincrease comfort, the thickness of the component may be tapered as itextends toward the posterior portions of the mouth on the buccal side oras the component covers less visible surfaces of the teeth.

Various attachment features can be used to couple an outer componentwith an appliance main body. Such attachment features can be used with avariety of outer component types or configurations (i.e., not just aveneer-type outer component). For example, an adhesive compound suitablefor use in a dental/oral environment can be used. An example of suchadhesive is a light curable aligner adhesive such as ClearLoc® (AlignTechnology, Inc,) The adhesive can be permanent or temporary. Temporaryadhesive would facilitate the re-usability of the outer component withmultiple inner components. Alternatively, various physical attachmentfeatures (undercuts, rivets, snaps, etc) can be used to secure the outercomponent to the main body. Such attachment features can include one ormore bumps, hooks, stepped ramps, or a combination thereof. For example,the outer component and the main body of the appliance can include oneor more reciprocal attachment features, such as a male protrusiondesigned to snap fit within a corresponding female receptacle. Such snapfit attachment features can provide the ability to removably attach anouter component with an appliance main body. Another example wouldinclude where one or more physical attachment features are secureddirectly to one or more of the patient's teeth. Such direct attachmentfeatures are sometimes used to allow for the application ofrepositioning forces in certain directions. An outer component can beconfigured to attach to one or more of these direct attachment features.Alternatively, an outer component can be configured to engage with aprotrusion or bump that may be formed in an aligner for another purpose,such as to engage a direct attachment feature secured to a tooth. Assuch, an outer component can be configured to couple with an appliancemain body having a treatment specific design in a variety of ways.Alternatively, an outer component and the main body of the appliance canbe integrally formed, thereby eliminating the need for attachmentfeatures.

In order to facilitate the use of a particular outer component with themain bodies of two or more distinct appliances, the attachment featureson the outer component and the main bodies of the appliances can bedesigned accordingly. As will be appreciated by a person skilled in theart, many variations in attachment features are possible that providethe ability to couple an outer component to the main bodies of two ormore different appliances. One such example would be the use of anindentation on the outer component that is wider or longer than aninterfacing bump on the main body of a first appliance, thereby allowingthe use of the indentation with a bump located in a slightly differentlocation on the main body of a second appliance. Additional approachesare described below.

Digital Development and Fabrication

As will be discussed in more detail below, various aspects of treatmentplanning used for positioning appliances can be advantageously employedto provide removable positioning appliances with the appearance of adesired tooth arrangement. Such treatment planning can include, forexample, planning methodologies and techniques as described in numerouspatents and patent applications assigned to Align Technology, Inc.including, for example in U.S. Pat. Nos. 6,450,807, and 5,975,893, theentire contents of which are hereby incorporated by reference. Duringtreatment planning, a digital representation of a patient's initialarrangement of teeth may be obtained by one of any number of methods,such as by scanning. The digital representation of the initialrepresentation can be manipulated to produce a target arrangement orplanned final arrangement digital representation. Both the initialarrangement digital representation and the planned final arrangementdigital representation can be used to produce a series of intermediatearrangement digital representations. The intermediate arrangementrepresent planned intermediate positions for the patient's teeth as theyare incrementally moved from their initial arrangement toward theirplanned final arrangements. The various arrangement digitalrepresentations produced can be used to define and/or produce a seriesof appliances for incrementally repositioning a patient's teeth fromtheir initial arrangement toward their planned final arrangement. Whiletreatment planning is described herein primarily in terms of computerbased or digital techniques, it will be recognized that the presentinvention can include or make use of various non-digital basedtechniques, including use of physical dentition modeling.

A series of appliances for use during a stage or course of treatment caninclude repositioning appliances shaped or configured to incrementallyreposition one or more teeth as the appliance is worn by the patient,and/or retention appliances shaped or configured to retain or hold teethin a desired arrangement such as a current arrangement. As noted, arepositioning appliance can include a plurality of tooth receivingcavities with one or more of the cavities shaped to apply repositioningforces so as to incrementally move one or more of the patient's teeth toa new arrangement. A retention appliance may similarly includetooth-receiving cavities with at least some of the cavities shaped toapply retention or positioning force(s) so as to restrain the patient'steeth from moving from a desired or current arrangement. During a courseof treatment, one or more appliances in the series of appliances of thetreatment plan can be used to restrain the patient's teeth for variouspurposes, such as to restrain the patient's teeth during a period oftime necessary to conduct an evaluation of whether the treatment isprogressing as planned or after a prescribed position has been obtainedso as to prevent a relapse.

Turning now to FIG. 6, an exemplary method 200 according to the presentinvention is illustrated. Individual aspects of method 200 are discussedin further detail below. While the following discussion is presentedmainly in terms of digital development of an integrated appliance usingcomputer aided design methods, it should be understood that non-digitalmethods can also be used and still be within the scope of the presentinvention.

As an initial step, data representing a patient's teeth at each stage ofan orthodontic treatment plan is received or produced (step 210).Typically, data representing a patient's initial or current arrangementof teeth is manipulated to produce a planned final arrangement for thepatient's teeth. Once the planned arrangement is produced, it is used inconjunction with the patient's initial or current arrangement to producea number of intermediate tooth arrangements or stages, which aresubsequently used to configure respective individual position adjustingappliances to sequentially move the patient's teeth between each of thestages. Although step 210 is illustrated as receiving digital data foreach stage of the treatment plan, as discussed above, such data canalternatively be generated as discussed above.

In steps 220 and 230, the desired appearance is determined andintegrated within a treatment plan by integrating the desired appearancewith one or more tooth positioning appliances corresponding to thetreatment plan. As was discussed above, and as will be discussed infurther detail below (see, e.g., FIGS. 7 and 8), both of these steps caninvolve many possible actions and related options. Because these stepsare discussed in further detail below, further discussion here isomitted.

In step 240, the integrated appliance having the desired appearance canbe optionally evaluated to determine whether structural and/orfunctional requirements are met. Exemplary structural and functionalrequirements can include a wide range of possible requirements, such as:flexibility; desired color, look, and feel; retention characteristics;weight; thicknesses required for the material or fabrication processused; resulting teeth positioning force characteristics; and protectivecharacteristics. Evaluation of appliance flexibility and teethpositioning force characteristics can be accomplished by a variety ofmethods, such as by finite element analysis or by a suitable parametricmethod. Exemplary finite element analysis methods that can be employedare described in U.S. Pat. No. 7,320,592, entitled “DEFININGTOOTH-MOVING APPLIANCES COMPUTATIONALLY,” the entire content of which ishereby incorporated by reference. Evaluation of structural and/orfunctional requirements can be accomplished with the aid of aconventional physical force measurement system or by a virtualinteraction with the integrated appliance, such as by display of theintegrated appliance on a suitable display screen. Exemplary physicalforce measurement system and method that can be employed are describedin U.S. patent application Ser. No. 11/881,528, entitled “ORTHODONTICFORCE MEASUREMENT SYSTEM.” Such virtual interaction can also includedisplay of a virtual representation of the patient's teeth, eithersimultaneous with the display of the integrated appliance, or alone.Such virtual interaction can help with the assessment of a range ofstructural or functional requirements, such as desired color, look,feel, and retention characteristics. Computer implemented methods canalso be used to determine the resulting weight of an integratedappliance.

An integrated appliance having the desired appearance can also include aprotective arrangement, such as a mouth guard used during varioussporting activities. The appliance material and thicknesses used caninfluence the level of protection that such a protective arrangementprovides. Appliance material properties can be considered in determiningthe configuration of the appliance so as to obtain the desired level ofprotection. The desired level of protection may vary with thecharacteristics of the sport played, such as position played, age of theplayer, the aggression level of the player, and the like. The protectivearrangement can be configured to reduce injury in a variety of ways,such as by providing a cushioning effect so as to reduce peak forcelevels transmitted within the body during an impact, and/or by providingfor dispersion of localized impact forces to surrounding tissues.Dispersion of localized impact forces can be enhanced by configuring theappliance having a protective arrangement to interface with teeth fromthe patient's upper and lower arches of teeth, thereby providing foradditional dispersion of impact forces.

In step 250, the results of any evaluation of the integrated appliancecan be used to decide whether to modify the integrated appliance. Instep 260, the integrated appliance can be modified as desired. A widerange of modifications are possible. For example, modifications caninclude any changes necessary to ensure that the integrated appliancemeets any of the structural and/or functional requirements evaluated instep 240. Many modifications to the integrated appliance can beaccomplished with the aid of automated methods. For example, analgorithm can be used to guide modification of the integrated applianceso as to achieve improved force and weight characteristics of theresulting appliance. Known computer aided design methods can be used tomodify the integrated appliance. The modified integrated appliance canthen be re-evaluated as described above in step 240. Evaluation andmodification of the integrated appliance can be repeated as desireduntil a final integrated appliance configuration is achieved. Once theintegrated appliance and/or outer component have been digitally defined,they can be fabricated (step 270).

Turning now to FIG. 7, an exemplary method for determining the desiredappearance (step 220) will now be described. Although a wide range ofpossible sources of desired appearances are possible, the method of FIG.7 shows three such sources. In steps 222 and 223, the final orthodontictreatment stage tooth arrangement for the patient can be selected as thedesired appearance. Selection of the patient's final treatment stagetooth arrangement may provide a number of benefits, such as providingthe patient with their future appearance prior to the end of the courseof orthodontic treatment. This can help to motivate the patient tocontinue with the planned orthodontic treatment or allow the patient tosee and experience their desired appearance and make changes ifunsatisfied.

In steps 224 and 225, the desired appearance can also be selected from anumber of predetermined digital templates of a wide range of possibledesired appearances. For example, such digital templates can includedigital models of one or more ideal teeth, and can also include digitalmodels of novelty tooth arrangements. These templates can include anynumber of individual teeth, from one to an entire arch. The desiredappearance can also be selected to include a combination of one or moreof the patient's teeth in a selected treatment stage arrangement and oneor more teeth from one or more selected templates. For example, thedesired arrangement can be a novelty arrangement, such as an arrangementfor Halloween that includes two fanged teeth 134 in place of the canineteeth of the upper arch (see FIG. 3C). Such an arrangement can be formedby a mixture of the patient's teeth in a selected treatment stage (suchas the final treatment stage) and two fanged teeth from one or more fangtooth templates. In another example, the desired arrangement can be anovelty arrangement for a holiday that includes one or more templateteeth representations in place of one or more of the patient's teeth,such as the patient's maxillary central incisors. As discussed above inconnection with FIG. 3C, many variations are possible and can beincorporated into template representations that can be used to formulatethe desired appearance. As illustrated in step 226, treatment stagesother than the final stage tooth arrangement for the patient can be usedto formulate the desired appearance.

Turning now to FIG. 8, an exemplary method for integrating the desiredappearance with an appliance (step 230) will now be described. In steps231, 232, 233, and 234, the exterior configuration of the integratedappliance is configured. It should be appreciated that the order of thesteps shown is not required, and that the steps can be practiced in anydesired sequence. For example, it may be preferred to first generate acombined representation (step 233) prior to scaling/modifying thedesired appearance (step 231). The generation of a combinedrepresentation (step 233) can involve the virtual combination of digitalmodels for the basic positioning appliance with digital models for theselected desired appearance. Evaluation of this combined representationcan help determine whether, or by how much, to scale and/or modify thedigital models for the selected desired appearance. Scaling of thedigital models for the selected desired appearance can be used toprovide for desirable proportions in the resulting combinedrepresentation. Modification of the digital models for the selecteddesired appearance can include relative positional modifications toensure proper placement/orientation of the selected desired appearancedigital models.

In step 231, the digital models for the desired appearance can be scaledand/or modified. At least where the selected desired appearance is thepatient's teeth in their final treatment stage, it will typically beadvantageous to scale up the desired appearance so as to generate acombined representation (step 233) where the outward facing visiblesurfaces of the combined representation are defined by the scaled updesired appearance. Without such scaling and/or modification, theoutward facing visible surfaces of the combined representation wouldtypically be at least partially defined by outward facing visiblesurfaces of the basic positioning appliance at that stage of treatment.

By scaling and/or modifying the patient's final teeth positions so as tosubstantially or wholly envelope the outward facing visible surfaces ofthe basic positioning appliances, a combined representation can begenerated that has outward facing visible surfaces that aresubstantially or wholly defined by the scaled and/or modified selecteddesired appearance.

In another embodiment, the desired appearance digital models can bescaled by a varying amount, such as scaling a particular portion of thedesired appearance by some amount, such as 10%, and progressivelyreducing the scaling factor for the other portions of the desiredappearance. For example, by scaling posterior portions of the desiredappearance by greater amounts than anterior portions of the desiredappearance, the scaled desired appearance can provide a wider appearancethat may serve to accentuate a patient's smile. When the desiredappearance has been selected to include one or more digital templatemodels, it may be necessary to scale and/or modify the template derivedvirtual teeth representations so their sizes and positions provide thedesired appearance in the integrated appliance.

Where the selected desired appearance is scaled and/or modified, variousapproaches can be used with regard to the amount of scaling and/ormodification. In a first approach, the selected desired appearance canbe scaled and/or modified so that it substantially or wholly envelopesthe forward visible surfaces of a particular basic appliance in theoverall series of appliances, for each appliance (see, e.g., FIG. 4C).This first approach may result in an integrated appliance with a minimumamount of material usage and least weight, but the outer surface maymove inward and outward during treatment until it is finally positionedoutward by the thickness of the appliance material during the last stageof treatment. However, this first approach may require moredevelopmental expense due to the added scaling and/or modificationeffort necessary for each basic appliance in a series of appliancesinvolved. In a second approach, the selected desired appearance can bescaled and/or modified so that it substantially or wholly envelopes theforward visible surfaces of a series of appliances (see, e.g., FIG. 4B).While this second approach may result in the use of additional amountsof material usage for some particular basic appliances in the series ofappliances involved, it will maintain the outer surface position andappearance until the later stages and may reduce developmental expensedue to the use of a common scaled and/or modified desired appearance aswould be required with the first approach (see, e.g., FIG. 4C).Additional approaches can also be used, such as a mixture of the abovediscussed first and second approaches. For example, the second approachcan be used earlier in the treatment where the patient's teeth arefurther away from their targeted final positions, and the first approachcan be used later in the treatment as the patient's teeth approach theirtargeted final positions.

The amount of any scaling and/or modification can also be influenced byintegration considerations. Where a separate veneer-type outer componentwill be integrated with an appliance main body, the resulting thicknessof the veneer-type outer component may be an important consideration,and the selected desired appearance can be scaled and/or modified toensure that the veneer-type outer component meets minimum thicknessrequirements. Where one or more attachment features are used to secure aseparate outer component to an appliance main body, the amount ofscaling and/or modification can be adjusted to ensure adequate space forthese attachment features.

Modification can also be used to improve the appearance for theresulting integrated appliance (i.e., the basic appliance and theassociated outer component). For example, it may be desirable to scaleand/or modify the desired appearance digital models where there areregions where the basic position adjusting appliance protrudes beyondthe outward facing visible surfaces of the combined representation.Modification can also be used to enhance the color of the appliance,such as in regions with relatively thin wall thickness between the outersurface and a particular tooth.

In step 232, the arch span for the desired appearance is selected. Theselected span can include one or more partial arch spans, or can be theentire arch. For example, the selected span can be limited to the morevisible anterior teeth. Limiting the selected span to the more visibleportions of the arch can help to avoid adding weight, size, and expenseto the integrated appliance by not modifying the basic appliance inareas where appearance is less important. An important consideration inselecting the arch span for the desired appearance is whether there willbe a separate outer component for the desired appearance, or whether thedesired appearance outer component will be integral with the basicpositioning appliance (step 235). As shown in FIGS. 5A and 5B, limitingthe selected arch span to the more visible anterior teeth can result ina smaller separate outer component that is more easily integrated withthe basic positioning appliance. When the desired appearance outercomponent will be integral with the basic positioning appliance, theselected arch span may have less of an impact on how easily the outercomponent is integrated with the basic appliance.

When a separate outer component is selected (in step 235), the method ofFIG. 8 includes additional steps for integrating the separate outercomponent with the basic positioning appliance. It should be appreciatedthat there are many possible approaches for integrating a separate outercomponent with a basic appliance. FIG. 8 includes two such approaches,specifically an outer component configured as a veneer-type component(step 237), and an outer component that is integrated with a basicappliance by way of adhesive or one or more discrete attachments (step238).

A known adhesive can be used to fix the component to the basicappliance. The step of adhering the component can occur duringmanufacturing or after the appliance and component have been shipped tothe doctor or user. By fixing the component to the appliance, the userwould only have one product to worry about storing, wearing, cleaning orlosing. However, just because the component may be adhered to oneappliance, does not mean the next component cannot be attached to theappliance by one or more discrete attachments.

As shown in FIGS. 5A and 5B, one of the many possible approaches forintegrating a separate outer component involves using a veneer-typeouter component (step 237). Such a veneer-type outer component can bedefined using a variety of different approaches. For example, theveneer-type outer component can be digitally defined by performing avolume or solid subtraction of the virtual representation of the basicpositioning appliance from the combined virtual representation. Theresulting virtual representation of the veneer-type outer component canbe further modified by subtracting additional portions from interfacingsurfaces of the veneer-type outer component so as to provide room for anadhesive layer between the veneer-type outer component and the basicpositioning appliance. As a further example, the combined representationcan be divided into two or more virtual parts by using a selectedinterface surface, where one of the resulting virtual parts correspondsto the main body of the basic positioning appliance and the otherresulting virtual part(s) corresponds to the veneer(s). The interfacesurface can be selected so as to provide interfacing surfaces of thebasic appliance and the veneer with preferred characteristics, such assuperior retention, or the ability to use a particular outer componentwith two or more different basic positioning appliance main bodies fortwo or more stages of an orthodontic treatment plan. When the same outercomponent veneer is to be used with two or more different basicappliance main bodies, the appliance main bodies can be configured witha common interface surface configuration corresponding to a matchingsurface on the common veneer-type outer component.

A separate outer component can also be integrated with a basic appliancemain body using one or more discrete attachments (step 238). Although asingle discrete attachment is possible where the attachment hassufficient rigidity, typically two or more discrete attachments would beused. It should be appreciated that a variety of different discreteattachments can be used. For example, the separate outer component andone or more basic appliance main bodies can be designed withcomplementary snap-fit features, such as a protrusion shaped to bereceived and retained within a complementary shaped receptacle. Asadditional examples, a discrete attachment can include one or morebumps, hooks, stepped ramps, or a combination thereof. The one or morediscrete attachments can also be designed so as to allow the use of aparticular separate outer component with two or more different basicappliance main bodies. For example, the discrete attachment(s) on onebasic appliance main body can share the same relative spatialorientation with the discrete attachment(s) on a different basicappliance main body, thereby providing identical interface points foruse with a common separate outer component. As an additional example,the discrete attachment(s) on different basic appliance main bodies canbe designed with limited directional clearances sufficient to accountfor different relative spatial orientations of the attachment(s) so asto couple with a common separate outer component. By using any of theabove attachment configurations, the user can remove the outer componentat any time. Reasons for removing the outer component may includecleaning, changing to present the patient's own appearance, changing toa new appearance, or just to remove the extra weight, discomfort, orawareness of the presence of the extra component.

It should be understood that a wide range of shapes and sizes ofcomponents are possible. In one embodiment, an outer component caninclude a substantially uniform or similar thickness (e.g., buccal tolingual thickness) partially or wholly along the arch span of thecomponent. In another embodiment, the component can include a varied orsubstantially non-uniform thickness (e.g., buccal to lingual thickness)along at least a portion of the arch span of the component. For example,component thickness can gradually increase or decrease along anincisor-to-molar or crown to gingival direction along a span of thearch. In yet another embodiment, the component can include substantiallychanging thickness (e.g., buccal to lingual thickness) between adjacentteeth so as to account for variations in distances between the outersurfaces of adjacent teeth and corresponding portions of the desiredappearance as might arise when one or more of a patient's teeth aresignificantly displaced from their planned final position (see, e.g.,FIGS. 4A-4C). Thus, the lingual side and occlusal surface of the alignerwill typically be thick enough to provide the desired force to move orretain the teeth. In addition, those aspects of the aligner on thebuccal side that are not visible when the user opens their mouth orsmiles may be thick enough to provide the desired force to move orretain the teeth.

Once an appliance (e.g., integrated appliance) and/or outer componenthave been digitally defined, they can be fabricated as illustrated inFIG. 9. Fabrication methods can employ a rapid prototyping device 272such as a stereo lithography or digital light projector machine. Anexemplary rapid prototyping machine is available from 3D System,Valencia, Calif. or EnvisionTEC, Gladbeck, Germany. The rapidprototyping machine 272 will selectively harden a liquid or othernon-hardened resin into a three-dimensional structure which can beseparated from the remaining non-hardened resin, washed, and used eitherdirectly as the appliance and/or outer component, or indirectly as amold for producing the appliance. The prototyping machine 272 willreceive the individual digital data sets corresponding to the integratedappliance and/or outer component, and produce one structurecorresponding to each.

In some cases, the rapid prototyping machine 272 can be used to producemolds which are, in effect, positive tooth models of each successivestage of the treatment. After the positive models are prepared, aconventional thermal vacuum forming machine 274 can be used to producethe basic appliances from a more suitable material, such as 0.03 inchthermal forming dental material. The machine 274 produces each of thebasic appliances directly from the positive tooth model and the desiredmaterial.

Where the outer component is produced as a separate veneer-typecomponent, it can be produced by a variety of different fabricationtechniques, including stereolithography (using ABS material, forexample), an automated computer aided cutting (e.g., CNC machine) ormolding process or even manually by providing a plastic template to theattending dentist for use in the creation of a separate veneer-typeouter component (using acrylic plastic, for example). A veneer-typeouter component can be fabricated using a variety of readily availabledental materials such as plastics, ceramics, and composite materials ina variety of color shades. Ideally, these conventional materials wouldbe extruded into a hollow shell to form the required veneer-typecomponent and then self-cure at room temperature or under the activationassistance of UV light into a hard rigid stain-resistant structure.

FIG. 10 is a simplified block diagram of a data processing system 300embodying the present invention. Data processing system 300 typicallyincludes at least one processor 302 which communicates with a number ofperipheral devices via bus subsystem 304. These peripheral devicestypically include a storage subsystem 306 (memory subsystem 308 and filestorage subsystem 314), a set of user interface input and output devices318, and an interface to outside networks 316, including the publicswitched telephone network. This interface is shown schematically as“Modems and Network Interface” block 316, and is coupled tocorresponding interface devices in other data processing systems viacommunication network interface 324. Data processing system 300 can be aterminal or a low-end personal computer or a high-end personal computer,workstation or mainframe.

The user interface input devices typically include a keyboard and mayfurther include a pointing device and a scanner. The pointing device maybe an indirect pointing device such as a mouse, trackball, touchpad, orgraphics tablet, or a direct pointing device such as a touch screenincorporated into the display. Other types of user interface inputdevices, such as voice recognition systems, are also possible.

User interface output devices typically include a printer and a displaysubsystem, which includes a display controller and a display devicecoupled to the controller. The display device may be a cathode ray tube(CRT), a flat-panel device such as a liquid crystal display (LCD), or aprojection device. The display subsystem may also provide non-visualdisplay such as audio output.

Storage subsystem 306 maintains the basic programming and dataconstructs that provide the functionality of the present invention. Thesoftware modules discussed above are typically stored in storagesubsystem 306. Storage subsystem 306 typically comprises memorysubsystem 308 and file storage subsystem 314.

Memory subsystem 308 typically includes a number of memories including amain random access memory (RAM) 310 for storage of instructions and dataduring program execution and a read only memory (ROM) 312 in which fixedinstructions are stored. In the case of Macintosh-compatible personalcomputers the ROM would include portions of the operating system; in thecase of IBM-compatible personal computers, this would include the BIOS(basic input/output system).

File storage subsystem 314 provides persistent (non-volatile) storagefor program and data files, and typically includes at least one harddisk drive and at least one disk drive (with associated removablemedia). There may also be other devices such as a CD-ROM drive andoptical drives (all with their associated removable media).Additionally, the system may include drives of the type with removablemedia cartridges. The removable media cartridges may, for example behard disk cartridges, such as those marketed by Syquest and others, andflexible disk cartridges, such as those marketed by Iomega. One or moreof the drives may be located at a remote location, such as in a serveron a local area network or at a site on the Internet's World Wide Web.

In this context, the term “bus subsystem” is used generically so as toinclude any mechanism for letting the various components and subsystemscommunicate with each other as intended. With the exception of the inputdevices and the display, the other components need not be at the samephysical location. Thus, for example, portions of the file storagesystem could be connected via various local-area or wide-area networkmedia, including telephone lines. Similarly, the input devices anddisplay need not be at the same location as the processor, although itis anticipated that the present invention will most often be implementedin the context of PCs and workstations.

Bus subsystem 304 is shown schematically as a single bus, but a typicalsystem has a number of buses such as a local bus and one or moreexpansion buses (e.g., ADB, SCSI, ISA, EISA, MCA, NuBus, or PCI), aswell as serial and parallel ports. Network connections are usuallyestablished through a device such as a network adapter on one of theseexpansion buses or a modem on a serial port. The client computer may bea desktop system or a portable system.

Scanner 320 is responsible for scanning casts of the patient's teethobtained either from the patient or from an orthodontist and providingthe scanned digital data set information to data processing system 300for further processing. In a distributed environment, scanner 320 may belocated at a remote location and communicate scanned digital data setinformation to data processing system 300 via network interface 324.

Fabrication machine 322 fabricates dental appliances based on data setinformation received from data processing system 300. In a distributedenvironment, fabrication machine 322 may be located at a remote locationand receive data set information from data processing system 300 vianetwork interface 324.

It is understood that the examples and embodiments described herein arefor illustrative purposes and that various modifications or changes inlight thereof will be suggested to persons skilled in the art and are tobe included within the spirit and purview of this application and thescope of the appended claims. Numerous different combinations arepossible, and such combinations are considered to be part of the presentinvention.

What is claimed is:
 1. A method of fabricating an orthodontic toothpositioning appliance with an improved appearance of a patients teeth,comprising: generating a first appliance portion having teeth receivingcavities shaped to receive and apply a resilient positioning force tothe patient's teeth; and generating a second appliance portion having asurface representing teeth having a selected appearance, wherein thesecond portion is configured for coupling with an outer surface of thefirst portion so as to represent the patient's teeth as having theselected appearance when the first portion and the second portionassembly is worn by the patient.
 2. The method of claim 1, wherein thesecond portion can be coupled with the first portion of a secondappliance.
 3. The method of claim 1, wherein generating the firstportion or the second portion comprises receiving a representation of anactulal arrangement of a patient's teeth and generating a digitalrepresentation of the patient's teeth in a planned arrangement.
 4. Themethod of claim 3, wherein the selected appearance represented by thesecond portion corresponds to the planned arrangement.
 5. The method ofclaim 1, wherein the first portion and second portion are integrated toform an integral appliance.
 6. The method of claim 5, wherein the firstportion and second portion are glued together.
 7. The method of claim 5,wherein the first portion and second portion are digitally combinedbefore manufacturing.
 8. The method of claim 5, further comprisingmodifying the integral appliance such that the appliance applies adesired repositioning force to the patient's teeth when worn.
 9. Themethod of claim 1, further comprising modifying the first applianceportion and/or the second appliance portion such that when worn by thepatient the combination of the first and second appliance portionsapplies a desired repositioning force to the patient's teeth.
 10. Amethod for digitally defining appliances for moving teeth, theappliances providing a desired appearance, comprising: receiving adigital representation of a patient's teeth for each stage of treatmentfrom an initial arrangement to a target arrangement; receiving a digitalrepresentation of teeth in a selected arrangement; creating a digitalrepresentation of an appliance main body for moving the patient's teethbetween each stage of treatment, each appliance main body havingdifferent teeth receiving cavity geometries shaped to receive andresiliently reposition the patient's teeth between two stages oftreatment; and modifying each appliance main body digital representationto create a digital representation of an appliance comprising an outercomponent having a surface representing teeth in the selectedarrangement.
 11. The method of claim 10, wherein the selectedarrangement represents the target arrangement.
 12. The method of claim10, wherein the modifying step comprises scaling up the selected digitalrepresentation and integrating the scaled up representation with anappliance main body digital representation.
 13. The method of claim 12,wherein the integrating step further comprises creating a digitalrepresentation of a separate outer component having an outer surfacethat provides a desired appearance, the separate outer component beingconfigured to couple with at least one appliance main body.
 14. Themethod of claim 13, wherein the integrating step further comprisescreating one or more digital representations of complementary shapedattachment features for coupling the outer component with at least oneappliance main body.
 15. The method of claim 10, wherein the teethmoving appliance comprises a protective arrangement, a prescribedarrangement, or a novelty arrangement.
 16. The method of claim 10,wherein the appliance digital representation is suitable for use inmanufacture or fabrication of the appliance.
 17. The method of claim 10,wherein the appliance digital representation is modified based upon analgorithm, the algorithm addressing repositioning forces, weight,material thickness, or color of the appliance outer surface.